Substrates such as wafers and reticles used in semiconductor processing are highly vulnerable to contaminants, including moisture, volatile organic components (VOC's), and particles. The presence of moisture, for example, can contribute to haze growth on both reticles and wafers. One way to control contaminants, including moisture, is to continually or periodically purge the space within a container where the substrates are stored or secured. During shipping, it has not been considered practical to use purging, and devices such as getters have been used within containers during shipping to keep moisture and VOC's to acceptable levels. Desiccants and other types of getters in substrate containers typically require removal or disassembly before the container is washed, as the fluids used can destroy the desiccants or getters.
Sealed containers known as FOUPs (front opening unified pods), FOSBs (front opening shipping boxes), or SMIF (standard mechanical interface) pods are used as wafer containers or reticle pods. These containers provide a microenvironment to isolate and control the volume surrounding wafers and substrates used in manufacturing integrated circuits. Such containers are available from Entegris, Inc., the owner of this application.
Due to the detrimental effect of moisture, VOC's, and particles on semiconductor production, improvements in the control of such contaminants can be desirable.